Mounting means



Feb. 9, 1965 v W. B. DUFFY ETAL MOUNTING MEANS Filed May 14, 1963 2Sheets-Sheet l INVENTORS WILLIAM & DUFFY BYRlCHARD A NARTMAW Feb. 9,1965 w. B. DUFFY ETAL MOUNTING MEANS Filed May 14, 1963 2 Sheets-Sheet 2I/IMLIIIIIIII l/nm/l INVENTORS WILLIAM B. DUFFY RICHARD A. HARTM/IN AH-or/my 3,169,007 MOUNTING MEANS William B. Dufiy, Berkeley Heights, andRichard A. Hartman, Madison, N..I., assignors to United-CarrIncorporated, a corporation of Delaware Filed May 14, 1963, Ser. No.280,382 7 Claims. (Cl. 248-343) The present invention provides for theexpeditious mounting of concealed lighting-fixture casings, and theinvention will be disclosed and discussed in that connection. Embracedwithin the invention are the organization as a whole, a subassembly anda gripping dog.

Concealed lighting-fixture casings or cans are commonly telescopedupwardly through an opening in the ceiling. Ordinarily the mouth of thecan is provided with an outwardly-extending annular flange which engagesthe under surface of the ceiling and limits the upward movement of thecan. Incorporated in the ceiling structure, and embracing the openingthrough which the casing or can is telescoped, is a sheet-metal plasterring. This ring may be circular or rectangular, depending upon whetherthe lighting-fixture casing is of circular or rectangular cross section.In accordance with what seems to be trade usage we will use the termplaster ring without regard to the material of the ceiling. In otherwords we will call the ring a plaster ring regardless of whether theceiling be of wet or dry construction, and regardless of I whether ornot the ceiling contains plaster.

Except for relatively expensive arrangements, the previously-usedarrangements known to us have a plaster ring that is provided with screwholes to receive horizontally-disposed screws for holding thelighting-fixture casing in mounted position. After telescoping thecasing into p osition in the ceiling, the installer reaches up throughthe mouth of the casing and inserts screws through openings in thecasing wall and threads them into the screwholes in the plaster ring.This is a cumbersome operation. After the installer has telescoped theeasing into the ceiling he has to adjust it to align the screw openingsin the casing Wall with the screw holes in the plaster ring. Then, whileholding the casing in adjusted position, he must insert the screws. Withonly two hands to work with, it is ditlicult for the installer to holdthe casing in adjusted position, hold the screw and, in addition,manipulate the screw driver. Moreover, the installation time is oftenlonger than might be supposed, particularly when one or more screws aredropped while attempting to get them started.

A prime object of the present invention is to overcome the foregoingdifficulties in the installation of concealed lighting-fixture casingsor cans.

Other objects of the present invention are to provide a concealedlighting-fixture-casing arrangement having some or all of the followingadvantages: (1) the casing can be facilely mounted through the openingin the ceiling, (2) no tools are required to effect the retention of thecasing in mounted position, (3) the casing can be installed by simplypushing it into position, (4) no special manipulation is required toadequately secure the installed casing, (5) additional securing of thecasing can be readily provided if desired, and (6) the mounted casingcan be removed or dismounted in practical manner.

An additional object of the invention is to provide a subassembly ofplaster-ring and locking-dogs which con- 3,169,0h7 Patented Feb. 9, 1965tributes to the accomplishment of some or all of the foregoing objects.

A further object of the invention is to provide a spring locking-dogwhich contributes to the accomplishment of some or all of the foregoingobjects.

Still further objects are to provide a mounting arrangement, aspring-locking-dog organization, and a spring locking-dog which areusable with analogous advantages for purposes other than the mounting ofconcealed lighting-fixture casings.

Other objects and advantages will be apparent from the detaileddescription hereinafter taken in connection with the drawings.

In both the description and the claims parts at times may be identifiedby specific names for clarity and convenience but such nomenclature isto be understood as having the broadest meaning consistent with thecontext and with the concept of our invention as distinguished from thepertinent prior art. The best modes in which we have contemplatedcarrying out our invention are illustrated in the accompanying drawingforming part of this specification. Except as otherwise indicated thedescription refers to the specific form or forms of the invention shownin the drawing; it does not necessarily refer to any other form in whichthe invention may be embodied. The claims, however, do embrace otherforms in which the invention may be embodied.

FIGURE 1 is a largely diagrammatic view showing a concealedlighting-fixture casing or can of the present invention telescoped intoa ceiling. The ceiling and plaster ring are shown in section and thelighting-fixture casing is shown in elevation.

FIGURE 2 is a fragmentary perspective view, on a larger scale, showingthe gripping of the lighting-fixture casing of FIGURE 1 at one of thevertical slots thereof.

FIGURE 3 is a top plan view of the spring locking-dog per se, that isshown gripping the casing in FIGURE 2.

FIGURE 4 is an elevation of the spring locking-dog per se, looking fromthe right of FIGURE 3.

FIGURE 5 is an elevation of the spring locking-dog per se, looking fromthe bottom of FIGURE 3.

FIGURE 6 is an elevation of the spring locking-dog per se, looking fromthe left of FIGURE 5.

FIGURE 7 is a fragmentary perspective view, on a much enlarged scale,showing the nose portion of the spring locking-dog that is shown inFIGURES 2 through 6.

FIGURE 8 is a fragmentary view in vertical section, with some parts inelevation, illustrating a preliminary step that is sometimes resorted toin the dismounting of a lighting fixture casing secured with dogs of thepresent invention.

FIGURE 9 is a fragmentary diagrammatic view, partially in verticalsection, showing a screw that may optionally be inserted into the springdog to additionally secure the lighting-fixture casing if desired.

FIGURE 10 is a diagrammatic plan view, looking toward the top of theceiling, showing an installation in which the lighting-fixture can isrectangular. The body of the rectangular can is shown in horizontalsection.

In FIGURE 1 the ceiling It has a circular hole 11 that is embraced by aplaster ring which is designated as a whole by 12. The ring 12 has avertical tubular portion 14 which lines the circular hole 11, and has awasherlike annular-flange portion 15 which is against the top surface ofthe ceiling 16*. The plaster ring 12 may be supported from the buildingstructure in any suitable manner, and the ceiling 11 may be of anysuitable material and be installed in any suitable manner. In one typeof installation the plaster ring is screwed or bolted to horizontalstraps or bars, often of strap iron or the like, which are secured tothe bottoms of consecutive joists. With the plaster ring thuspremounted, the ceiling is installed in relation to the plaster ring.Sometimes the ceiling has a plaster coating which is applied wet andtroweled into position against the plaster ring.

The lighting-fixture can or casing is designated as a whole by 17 it isof formed sheet-metal, often aluminum. It has a hollow cylindrical bodyor wall 18 which may be necked in at 19 as it approaches the closed end20 of the casing. The mouth of the casing is open and it is providedwith an integral annular flange 21 which encircles the body or wall 18and projects outwardly therefrom. Before the casing 17 is telescopedinto the ceiling 10 an electrical cable 24 is brought downwardly throughthe hole 11 in the ceiling and suitably connected to the casing 17 andthe lighting fixture thereof. Then the casing 17 is telescoped upwardlythrough the ceiling, bringing the casing to the position shown in FIGURE1 with the flange 21 against the bottom surface of the ceiling.

The casing-wall 18 is provided with vertical slots 22 which are equallydistributed about the circumference of the wall 18. For each slot 22 inthe casing-wall 13 the plaster ring 12 has a spring locking-dog 25 whichis aligned with and engages the slot 22 as shown in FIGURE 2. Thesespring locking-dogs 25 hold the casing 17 in mounted position in theceiling, as will be explained.

The slots 22 have a vertical extent and a vertical position such asshown in FIGURE 1. For many installations three slots 22, spaced 120degrees apart, are suitable; and three slots 22 is what FIGURE 1 shows.For some in stallations a larger or smaller number of slots 22 might beused.

- The character of the spring dog 25 will be understood from aconsideration of FIGURES 2 through 7. The dog is formed of sheet metaland has legs 26 and 27 which are at an obtuse angle to each other. Thefree end 28 of the leg 26 is upturned and, near such free end, a springlatching-finger 29 is struck upwardly from the body of the leg 26. Nearthe juncture of the legs 26 and 27 the leg 26 is provided with twoshoulders 30, one on each side of the leg as shown. The leg 26 isgenerally flat and is adapted to be attached to a suitable support suchas the plaster ring 12.

A Each of the spring dogs 25 with which the plaster ring 12 is equippedis secured to the plaster ring as shown in FIGURE 2. Struck upwardlyfrom the horizontal annular-fiange 15 of the plaster ring is a straplikesheet-metal bridge 16. The leg 26 of the dog 25 is telescoped under thebridge, with the leg 27 of the dog facing inwardly of the plaster ringas in FIGURE 2. In telescoping the leg 26 under the bridge 16, the dogis first canted so that the upturnedv end 23 of the leg 26 can beentered under the bridge 16 at the edge thereof which faces toward theinside of the plaster ring. Then the dog 25 is swung downwardly to bringthe leg 26 in parallelism with the flange 15. As the leg 26 is forciblytelescoped beneath the bridge .16, the latching finger 2% is flexeddownwardly by engagement with the bridge. As the telescoping movement iscompleted, the two shoulders 30 engage that edge of the bridge 16 whichfaces toward the inside of the plaster ring and the latching finger 29snaps out into latching relationship with that edge of the bridge whichfaces toward the outside of the plaster ring.

With the spring dogs 25 attached to the plaster ring 12-, one dog foreach slot 22, the legs 27 of the dogs extend. inwardly of the tubularportion 14 of the plaster ring and the tips of the noses of the dogs lieon a circle that is somewhat smaller than the circumference of the bodyor wall 18 of the lighting-fixture casing 17. The

noses 35 are V-shaped as will more fully appear. As the lighting-fixturecasing is telescoped into the mounted position shown in FIGURES l and 2,the casing wall 18 cammingly engages the noses 35 of the spring dogs andforces them outwardly, thereby affording ready telescoping of the casing17 to the mounted position shown in FI URES 1 and 2.

If the slots 22 are in alignment with the noses of the dogs 25 as thecasing 17 is telescoped to mounted position, the V-shaped noses 35 ofthe dogs will enter the slots and engage the opposite edges thereof asshown in FIG- URE 2. As the casing 17 is approaching its terminalposition shown in FTGURES 1 and 2 the installer checks, by rotative feelapplied to casing 17 or otherwise, to ascertain whether the noses 35 ofthe spring dogs are in the slots 22. If they arent, the installerrotates the casing 17 about its vertical axis until the noses 35 of thedogs 25 snap into the slots 22. If-the circumferential spacing of theslots 22 is accurate, and if the corresponding circumferential spacingof the dogs 25 is accurate, perfect alignment of each dog 25 with a slot22 will be achieved. However, our construction will accommodate ameasure of inaccuracy in the circumferential spacing of the slots 22,the dogs 25, or both. The two shoulders 36 and the latching finger 29 ofthe dog 25 serve to maintain the holding relationship between the bridge16 and the locking dog 25 even with considerable looseness or lostmotion between the dog and the bridge. We provide such looseness or lostmotion, whereby each dog 25 can shift a little and can also pivotsomewhat on a vertical axis passing approximately through the center ofbridge 16. This renders each of the dogs 25 individually self-adjusting,to a reasonable extent, to effect correct engagement of the V-shapednose 35 of the dog with its companion slot 22 despite reasonableinaccuracy in the circumferential position of the dog or the slot orboth.

The leg 27 of the dog 25 has two triangular side portions 34 which arebent backwardly and provide the leg 27 with the V-shaped nose 35 thatenters and engages the slot 22 of the lighting-fixture can 17; seeFIGURE 2. The ends 34a of the bent-back portions 34 are hooked towardthe wall 18 of the lighting-fixture can 17, being bent along lines 34b.The metal is so sheared that the tips of these hooked ends 34a have theshearing burrs in engagement with the edges of the slot 22. Upon anattempt to move the mounted can 17 downwardly, the burred edges of theends 34a bite into the edges of the slot 22. The plurality of fasteners25 with which the plaster ring 15 is equipped co-operate to maketogglelike gripping engagement with the casing 17, which grippingengagement increases as downward force applied to the mounted casingincreases. To mount the casing 17 it is only necessary to telescope itto the position shown in FIGURE 1 with the slots 22 aligned with thedogs 25, whereupon the casing is firmly held in mounted position by thetogglelike gripping action of the spring dogs 25.

The triangular bent-back portions 34 are, among other things, cams whichare adapted to come into play if and when it is desired to dismount thecasing 17. By forcible rotation of the casing 17 about its verticalaxis, in either direct-ion, one of the triangular bent-back sideportions 34 of each dog 25 is cammingly acted upon by an edge of theslot 22 with which the dog is engaged. The legs 27 of the dogs areflexed outwardly and, as the surface of the casing-body 18 movessidewise with respect to the dogs 25, the smooth unslotted surface ofthe casing moves under the noses 35 of the dogs. Each nose 35 has asmall fiat 38, shown in FIGURE 7, which slidably engages the unslottedsurface of the casing-wall 18. The plane of the flat 38 is substantiallyvertical and is now substantially tangent to the surface of thecasing-body 18, with the result that the holding grip of the spring dogon the casing has now been eliminated and the easing 17 can be pulleddownwardly and dismounted.

As perhaps best seen in FIGURE 2 the leg 27 of the spring dog 25 has alongitudinally extending slot 40 which, at the midpoint of its length,is enlarged into a circular hole 41. The slot 40 is useful in carryingout a preliminary step that is sometimes resorted to in dismounting thecasing. In a few installations the mounting casing, e.g. casing 17' inFIGURE 8, presents nothing that can be conveniently gripped to forciblyrotate it and cam the spring dogs out of engagement with the slots 22.In such case a screw-driver blade 44 may be inserted through the slot 22as shown in FIGURE 7, the tip of the blade be engaged in the slot 40 ofthe spring dog 25, and then the screw driver be pushed to flex the leg27 outwardly to the dotted-line position shown in FIGURE 8. It will beunderstood that the blade 44 of the screw driver is wedge-shaped inthickness and that the width of the slot 40 is such that only the tip ofthe blade passes through the slot. With the leg 27 disengaged from thecasing wall 18, downward prying force can be exerted with thescrew-driver blade to move the adjacent portion of the casing downwardlya little. By progressing from spring dog to spring dog in this mannerwith a screw driver, the casing can be walked downwardly sufficiently toenable the flanfe at the mouth of the casing to be gripped for forciblerotation of the casing and dismounting of the same as already explained.

The normal gripping action of the spring dogs 25 is such that they willsustain a relatively heavy load. Specifically we have found that with analuminum casing 17 that is thick a downward force of as much as fortypounds per locking dog 25 can be safely imposed. With such highload-sustaining capacity per locking dog it is apparent that in someinstallations a single spring locking-dog would suffice if theinstallation provided a sheath or other suitable means to maintain thealignment of the mounted member.

With such high holding forces by the normal gripping action of the dogs25, further support is rarely required. However, additional support canbe provided by inserting a pan-headed sheet-metal screw 48 through oneor more of the slots 22 as indicated in FIGURE 9. The arrow 48 isthreaded into the round hole 41 of the spring dog 25. The head of thescrew spans the slot 22 and the thread of the screw elfects some helicalflexing of the margin of the hole 41 without need for flowing metal ofthe spring dog.

A lighting-fixture casing which is rectangular in cross section may beinstalled in like manner and be removed in analogous manner. Usually thewall of the casing will have four or more slots 22, divided between theopposite sides of the casing. The plaster ring will be rectangular inconformity with the rectangular form of the casing. In FIGURE there isshown schematically a rectangular lighting-fixture casing 17", having avertical wall 18" and an outwardly-extending annular flange 21" at themouth of the casing. One side of the casing wall 18" has two verticalslots 22 which are the same as the slots 22 in FIGURE 1. The oppositewall of the casing has two like vertical-slots 22. The rectangularplaster ring 12 has a washerlike flange 15" which is on top of theceiling 10" and carries four of the spring locking-dog 25, one for eachof the slots 22 in the easing. The V-shaped noses 35 of the springlocking-dogs engage in the slot 22', the same as in FIGURE 2. At leastone-half inch of space is allowed at S and S between the wall 13" of therectangular lighting-fixture casing and the confronting face of theplaster ring. This is so that the lighting-fixture casing 17 can bebodily shifted in a srtaight line to either the right or the left of theposition shown in FIGURE 10 to cam the noses 35 of the locking dogs outof the slots 22 and bring them into sliding engagement with the wall 18of the casing 17" for dismounting of the casing as already explained.

In the drawing the thickness of sheet metal is necessarily exaggerated.We have stamped the spring locking-dog 25 from annealed spring steel.020" thick, and hardened and tempered the dog after forming. Also, wehave used the following approximate dimensions:

Over-all length of the spring dog as viewed in FIGURE 3 Q inches Lengthof leg 26 as viewed in FIGURE 3, taken from the free end of the leg toits juncture with leg 27 "inches" Width of the mid portion of leg 26 asviewed in FIGURE 3 inches Width of the widest part of leg 26, viz. atits junction with leg 27 inches Dimension of upturned end 28 lengthwiseof leg 2e and as viewed in FIGURE 3 inches Perpendicular distance fromlower face of leg 27 in FIGURE 5 to a parallel plane which passesthrough the two free corners of the bent-back triangular portions (34including 34a), one of such free corners being seen in FIGURE 5, andboth of such free corners being seen in FIGURES 3, 4, 6 and 7 inchesWidth of bridge 16 radially of plaster ring 15 inches Angle between legs26 and 27, with the dog 25 unstressed, degrees Inclination of leg 27 tothe wall 18 of the lightingfixture casing before the dog is stressed,degrees We claim:

1. A plaster ring to telescopically receive a lightingfixture casing;and a plurality of spring dogs distributed about the ring, each dogbeing of sheet metal and having two degs at an obtuse angle to eachother, one leg being attached to the ring, and the other leg projectinginto the path of a lighting-fixture casing telescoped into the ring,said other leg having a V-shaped nose to grippingly engage a verticalslot in the lighting-fixture casing.

2. A plaster ring to telescopically receive a lighting fixture casing;and a plurality of spring dogs distributed about the ring, each dogbeing a single piece of sheet metal and having two legs at an obtuseangle to each other, one leg being attached to the ring, the other legprojecting into the path of a lighting-fixture casing telescoped intothe ring, said other leg having a V-shaped nose to grippingly engage avertical slot in the lightingfixture casing, and the tip of the nosebeing flat for nongripping sliding movement of the casing thereover whenthe nose is in engagement with an unslotted portion of the casing.

3. A slotted member mounted by telescopic movement of the member in thedirection of the length of the slot, and a spring dog having a V-shapednose engaging the slot and strongly opposing reverse movement of themember, the nose including a cam surface operable upon sidewise relativemovement of the mounted member and the dog to cam the nose of the dogout of the slot and release the member for dismounting.

4. A one-piece spring dog composed of sheet metal, the dog having agenerally flat leg for attachment to a support and having a second legfor engaging and holding a member, the two legs being at an obtuse angleto each other and the second leg having side portions which are bentback and provide the second leg with a V-shaped nose for making holdingengagement with a slot in said member.

5. A one-piece spring dog composed of sheet metal, the dog having agenerally flat leg for attachment to a support and having a second legfor engaging and holding a member, the two legs being at an obtuse angleto each other and the second leg having side portions which are bentback and provide the second leg with a V-shaped nose for making holdingengagement with a slot in said member, and the tip of the nose having aflat which is adapted to make sliding engagement with unslotted portionsof said member.

6. A spring dog having a leg for attachment to a support, and having asecond leg for engaging and holding a member, the second leg having aV-shaped nose for engaging a slot in said member and also having a holefor the reception of a screw to additionally hold said member. 7

7. A spring dog composed of a single piece of sheet metal, the doghaving two legs at an obtuse angle to each other, the first leg being asupport leg for attachment to a support, and the second leg being a gripleg for gripping and holding a member, the tip of the second leg beinghooked toward the member for making the gripping engagement therewith,and the end portion of the second leg being V-shaped for engagement ofthe tip of the leg with a slot in said member.

References Cited by the Examiner UNITED STATES PATENTS 2,793,071 5/57Meyer 4-187 2,885,691 5/59 Juergens 4-187 2,888,684 6/59 Icenhower 4-1872,914,287 11/59 Henning 248-343 2,965,348 12/60 Gerstel et al 248-3432,992,315 7/61 McDonnold 4-187 10 3,018,083 1/62 Bobrick 248-343 FOREIGNPATENTS 1,013,237 8/57 Germany.

CLAUDE A. LE ROY, Primary Examiner.

UNITED STATES PATENT OFFICE EERTlFlQA'lE 61F QQRREUHQN Patent No.3,169,007 February 9, 1965 William B. Duffy et al It is hereby certifiedthat error appears in the above numbered patent requiring correction andthat the said Letters Patent should read as corrected below Column 5line 24, for "flanfe" read flange lines 41 and 42 for "arrow read screwcolumn 5, lines 57, 62 and 64 for "22 each occurrence, read 22 line 62,for "locking-dog" read locking-dogs line v69 for "srtaight" readstraight column 6, line 33, for "degs" read legs Signed and sealed this27th day of July 1965 (SEAL) Attest:

ERNEST W. SWIDER EDWARD J, BRENNER Attesting Officer Commissioner ofPatents

1. A PLASTER RING TO TELESCOPICALLY RECEIVED A LIGHTINGFIXTURE CASING;AND A PLURALITY OF SPRING DOGS DISTRIBUTED ABOUT THE RING, EACH DOGBEING OF SHEET METAL AND HAVING TWO LEGS AT AN OBTUSE ANGLE TO EACHOTHER, ONE LEG BEING ATTACHED TO THE RING, AND THE OTHER LEG PROJECTINGINTO THE PATH OF A LIGHTING-FIXTURE CASING TELESCOPED INTO THE RING,SAID OTHER LEG HAVING A V-SHAPED NOSE TO GRIPPINGLY ENGAGE A VERTICALSLOT IN THE LIGHTING-FIXTURE CASING.